/**
 * @param {String} type = Point|LineString|Circle|Polygon|Square|Box
 *  */
function createDraw({
    type = "Point",
    source,
    success
}) {
    let geometryFunction = null;
    let maxPoints = null;
    if (type == "Box") {
        type = "LineString"
        geometryFunction = function (coordinates, geometry) {
            if (!geometry) {
                //多边形
                geometry = new ol.geom.Polygon(null)
            }
            var start = coordinates[0]
            var end = coordinates[1]
            geometry.setCoordinates([
                [start, [start[0], end[1]], end, [end[0], start[1]], start],
            ])
            return geometry
        }
        maxPoints = 2;
    } else if (type == "Square") {
        type = "Circle";
        geometryFunction = ol.interaction.Draw.createRegularPolygon(4)
    }
    let draw = new ol.interaction.Draw({
        type,
        source,
        geometryFunction,
        maxPoints
    })
    if (success) {
        draw.on("drawend", evt => {
            success(evt.feature)
        })
    }
    return draw;
}